diff --git a/src/main/java/com/cool/hot100/backtracking/Num79.java b/src/main/java/com/cool/hot100/backtracking/Num79.java
new file mode 100644
index 0000000..a6c483e
--- /dev/null
+++ b/src/main/java/com/cool/hot100/backtracking/Num79.java
@@ -0,0 +1,54 @@
+package com.cool.hot100.backtracking;
+
+/**
+ * Created with IntelliJ IDEA.
+ *
+ * @Author: Cool
+ * @Date: 2024/09/11/21:21
+ * DayNumber 1
+ * Hard 2
+ * Level 4
+ */
+public class Num79 {
+
+    public boolean exist(char[][] board, String word) {
+        if (board.length < 1) {
+            return false;
+        }
+        for (int i = 0; i < board.length; i++) {
+            for (int j = 0; j < board[0].length; j++) {
+                if (board[i][j] == word.charAt(0)) {
+                    if (dfs(board, word, i, j, 0)) {
+                        return true;
+                    }
+                }
+
+            }
+        }
+        return false;
+    }
+
+    private boolean dfs(char[][] chars, String word, int x, int y, int index) {
+        if (index == word.length()) {
+            return true;
+        }
+        if (x < 0 || x >= chars.length || y < 0 || y >= chars[0].length) {
+            return false;
+        }
+        if (chars[x][y] == '1') {
+            return false;
+        }
+        boolean is = false;
+        if (word.charAt(index) == chars[x][y]) {
+            char temp = chars[x][y];
+            chars[x][y] = '1';
+            is =dfs(chars, word, x + 1, y, index + 1) || dfs(chars, word, x, y + 1, index + 1)
+                    || dfs(chars, word, x - 1, y, index + 1) || dfs(chars, word, x, y - 1, index + 1);
+            chars[x][y] = temp;
+            return is;
+        } else {
+            return false;
+        }
+    }
+
+}
diff --git a/src/main/java/com/cool/week414/Problem1.java b/src/main/java/com/cool/week414/Problem1.java
new file mode 100644
index 0000000..f91617b
--- /dev/null
+++ b/src/main/java/com/cool/week414/Problem1.java
@@ -0,0 +1,36 @@
+package com.cool.week414;
+
+/**
+ * Created with IntelliJ IDEA.
+ *
+ * @Author: Cool
+ * @Date: 2024/09/08/11:28
+ * ProblemNumber
+ */
+public class Problem1 {
+    public String convertDateToBinary(String date) {
+        String[] dates=date.split("-");
+        String res="";
+        for(int i=0;i<dates.length;i++){
+            int dateInt=Integer.parseInt(dates[i]);
+            res+=trans(dateInt);
+            if(i!=dates.length-1){
+                res+="-";
+            }
+        }
+        return res;
+    }
+
+    private String trans(int date){
+        if(date==0){
+            return "0";
+        }
+        String res="";
+        while(date!=0){
+            int num=date%2;
+            date=date/2;
+            res=String.valueOf(num)+res;
+        }
+        return res;
+    }
+}